Validation of a Simplified SRS-Schwab Classification Using a Sagittal Modifier.

Area of Science:

• Orthopedics
• Spine Surgery
• Radiology

Background:

• The SRS-Schwab classification for adult spinal deformity (ASD) has 27 sagittal parameters, making it complex for clinical use.
• Accurate classification is crucial for determining surgical indications in ASD patients.

Purpose of the Study:

• To validate the accuracy of Schwab's classification for surgical indication.
• To evaluate a simplified, three-category sagittal modifier for ASD.

Main Methods:

• A prospective study of 1,004 adult spinal deformity patients was conducted.
• Patients were classified using sagittal vertical alignment (SVA), pelvic tilt (PT), and pelvic incidence-lumbar lordosis (PI-LL).
• A novel three-category system (Aligned, Moderate, Severe) was developed and compared to the original 27 possibilities.

Main Results:

• Significant differences in health-related quality of life (HRQoL) scores and surgical indications were observed across the 27 possibilities.
• The simplified three-category system demonstrated comparable results, with significant differences found when comparing subgroups.
• No significant differences in HRQoL or surgical indication were found within the simplified categories themselves.

Conclusions:

• The proposed three-category simplification of the SRS-Schwab classification enhances readability.
• This simplified system could potentially replace the current complex sagittal modifiers for ASD.
• The simplified classification, used with other parameters, may aid in surgical decision-making for ASD patients.